A man accused of fatally stabbing a teenager during a brawl outside an Adelaide nightclub has told a Supreme Court jury he had feared for his life and acted in self-defence.
Four men are on trial accused of murdering 19-year-old Christopher Hatzis in Light Square in August 2012.
It is alleged David Zefi, 23, repeatedly stabbed Mr Hatzis with a knife, while Rrok Jakaj, 20, Dario Stakaj, 21, and a now 19-year-old man held him down, and kicked and punched him.
The prosecution's case is that while Zefi was responsible for the fatal injuries, each of the men were part of a plan to cause Mr Hatzis grievous bodily harm, and therefore each was equally responsible for his death.
Giving evidence in his defence, Zefi told the court he stepped in when Mr Hatzis attacked his cousin and a friend.
He said Mr Hatzis had punched and knocked unconscious one man, and was holding the other when he pulled them apart.
Zefi said it was then Mr Hatzis punched him in the side of the head.
"I grabbed him in a headlock to stop him from punching me, but he was going crazy. I was trying to get him on the ground. He bit me [on my chest]. It hurt. I let go and I fell downward," he said.
"When I was getting up he had a knife in his hand. He said 'You're f**** dead c***', that's the words I remember. [I thought] that I would die.
"I grabbed his hand. He was waving the knife around my hands. I pushed the knife towards him. He bit me on the shoulder.
"We were fighting for the knife. Our hands were everywhere. He was going to kill me and I wanted to stop him from hurting me.
"Everything was going so fast. It was just me and him fighting. It stopped. He wasn't biting as hard and then the knife fell and that was my opportunity, so I ran.
"I got away from him. I was scared and when I got to the car I realised my top was ripped, my hands were bleeding.
"He still wanted to fight with me. I didn't want to fight. I was hurt. Why would I want to fight with him? I didn't go out to fight with people, I went out for fun.
"I had no chance to get away. If I had tried to get away he would have stabbed me in the back."
Zefi admitted he had stabbed Mr Hatzis but did not know how many times.
He said Mr Hatzis was still fighting someone else when he ran away, and had called out to Zefi to come back and fight.
Zefi said he only found out Mr Hatzis had died the next day.
"I thought he was hurt but I didn't think he was badly hurt," he said.
"The next day I found out he was dead.
"My family called a lawyer because I was going to go to police."
Zefi said he knew the other accused men from within the Albanian community but he did not see them that night, nor did he know if they had been involved in any fighting.
He said as far as he was aware, he was involved in a one-on-one fight.
The trial continues.